They revive sailors with BO (8,5)
I believe the answer is:
smelling salts
'they revive' is the definition.
(I've seen this before)
'sailors with bo' is the wordplay.
'sailors' becomes 'salts' (salt is a kind of sailor).
'with' says to put letters next to each other.
'bo' becomes 'smelling' (I am not sure about this - if you are sure you should believe this answer much more).
'salts' put after 'smelling' is 'SMELLING-SALTS'.
Can you help me to learn more?
(Other definitions for smelling salts that I've seen before include "could bring you round" , "Restorative to be sniffed" , "stimulant" , "Sal volatile" , "Pungent ammonium carbonate crystals" .)